The present invention relates to a diagnostic test method for detecting malignant neoplasms.
The neoplastic process in human beings has been, and still is, the subject of intensive study. In order to obtain a better understanding of the disease, human cancer tissue has been studied in an effort to discover the cause, treatment, prevention and diagnosis of cancer. Early diagnosis of cancer is very important since it increases chances of effecting a complete remission of the disease.
In an effort to utilize known diagnostic tools to detect the presence of malignant tumors, attempts have been made to demonstrate tumor specific components, such as hormones or antigens. These attempts have been unsuccessful with many types of malignant tumors, since it has not been possible to segregate normal tissue antigens from abnormal cancer antigens and demonstrate the specificity of the cancer antigens or it has not been possible to demonstrate tumor specific components.
In the efforts to isolate abnormal cancer antigens and demonstrate their specificity, attempts have been made to cause the formation of tumor-specific antibodies and demonstrate their presence in sera obtained from animals immunized with preparations of human cancer. If consistently reproducible, the demonstration of the presence of tumor-specific antibodies in animal antisera would lead to the use of a valuable diagnostic tool.
In order to fully utilize the existence of tumor-specific antibodies in animal fluids, a diagnostic test must be developed which will demonstrate the presence of the tumor antigens in the blood of the patient. Procedures which have been devised have not proven efficient or sensitive in the detection of and differentiation between carcinomas originating at different locations in the body, either primary or as a result of metastasis.
Efforts to abstract relatively pure antigens associated with carcinomas have met with either no success or are impractical from a commercial point of view, since a process has not been found to make it possible to completely segregate such as antigen from normal tissue antigens and non-antigenic materials.
Various examples exist in the prior art which are directed to a method of detecting abnormal tissues through the use of radioactively tagged compounds. In a specific example wherein a radioactively labelled compound is used to determine disease tissue, the sample of cells from a body under investigation is treated with a radioactively tagged substance which is determined to be selectively absorbed by one or more predetermined cell types sought to be identified either as disease-producing cells or abnormal cells of the body and distinguished from other cell types. The radioactively tagged substance is absorbed in different amounts by some cells and rejected by other cells. After treatment and washing, the level of radioactivity of the cell sample is sensed in order to determine, from the degree of absorption of the radioactively tagged substance, information about the presence or absence of disease. The technique may be applied to mass screening for disease of a particular type, or types, by collecting and identifying similar samples from many subjects and using a predetermined common standard of radiation level to eliminate those samples which are clearly free from disease. A major disadvantage of the foregoing process is that the procedure involves fixed sample, that is, samples of dead tissue cells or microorganisms, and is best employed where hundreds of samples of the same kind are to be considered. The instant invention is effected through the utilization of living subjects and indicates a relatively high rate of accuracy in identifying malignant neoplasms, which may occur in any part of the subject under investigation.
Other areas of the art relate to methods of isolating and characterizing the antigen components referred to as carcinoembryonic antigens which are associated with various carcinomas to establish diagnostic test procedures. These methods require extensive procedures to enable the components of the carcinoembryonic antigens to be separated and additional processes must be directed to the structural characterization of the carcinoembryonic antigens isolated in addition to a process for the radioactive tagging of the specific antigens of interest. The specificity of this method is very low and detection in the early stages very difficulty since the antigen concentration only increases as the tumor progresses.